1. Field of the Invention
The present invention relates to a photographic film carrier carrying a photographic film on which image frames are consecutively recorded, and positioning the respective image frames at a print position in order, more particularly to a method of controlling an output condition of an abnormality signal in the photographic film carrier for controlling the output condition of the abnormality signal output when detecting abnormality, and an apparatus thereof.
2. Description of the Related Art
A photoprinter is provided with a negative carrier at a print position for, in order, positioning image frames of a negative film at the print position after development of the film. The negative carrier comprises a base and a cover body which can open and close with respect to the base. The base has a negative film guide path provided with a printing opening corresponding to an image frame. The guide path has driving rollers at positions corresponding to the vicinities of both the lateral edges of the negative film. The driving rollers are rotated by a driving force of a pulse motor. The cover body is provided with idle rollers paired with the driving rollers to hold the negative film between the rollers and idle rollers. Thus, these driving rollers allow to hold and carry the negative film along the guide path when the cover body is closed and the negative film is inserted into the negative carrier from one side thereof.
A detecting apparatus for detecting an image frame edge is mounted upstream the printing opening of the guide path. The detecting apparatus, as disclosed in Japanese Patent Application Laid-Open No. 3-11329, is provided with a cold-cathode tube or a halogen lamp at the rear side of the guide path, and a slit hole formed in the guide path. In the detecting apparatus, each image frame of the negative film on the guide path is irradiated with a light emitted from the cold-cathode tube or halogen lamp.
The cover body is provided with a light receiving sensor corresponding to the slit hole so that light transmitted through the negative film can be received by the sensor. Transmission density of the negative film can be calculated based on quantity of received light detected by the light receiving sensor. Generally, a base portion of the negative film has a low transmission density while the negative film has a high transmission density within the range of the image frame. It is possible to compare a difference between the transmission density of the base portion and that of the image frame with the predetermined transmission density to detect a boundary between the image frame and the base portion, i.e., the image frame edge. The image frame edge allows to position the respective image frames of the negative film at the print position.
Therefore, it is possible to position each image frame of the negative film at the print position automatically and accurately even if the pitches of the respective image frames recorded on the negative film are fluctuated depending on feeding errors in photographing by a camera. Thus, the feeding error due to a quantitative feeding can be eliminated. In addition, the negative carrier itself can be simply constructed because it is not necessary to detect a notch provided for each image frame.
In such a control for positioning, a front edge of each image frame generally serves as a reference edge when it is normally spaced from the preceding image frame. If abnormally spaced, it is detected whether or not the back edge of the image frame is normally spaced from the preceding image frame. If normally spaced, the back edge can be used as the reference edge. If neither front nor back edges are normally spaced, the negative film is quantitatively fed on the basis of a state where the preceding image frame is positioned.
However, in the conventional positioning method as set forth above, unstable detection may be made depending on the image frames recorded on the negative film. That is to say, in some cases, adjacent image frames may be overlapped with each other, it may be difficult to distinguish the image frame from the base portion due to overexpose, and the edge portion may be unclear due to overexposure. In these cases, the detected edge is incorrect per se so that accurate positioning may not be made even if it is tried on the basis of the preceding image frame.
In case of detecting such an abnormality, the negative carrier is adapted to output an abnormality signal. The abnormality signal is fed into a controller of the photoprinter so that the controller controls the photoprinter to interrupt a process and to alert an operator to the abnormality by an alarm and so on. This system allows the operator to correct for a proper positioning compensation when accurate positioning can not be made in the automatic positioning control.
However, there may be a great diversity of abnormality causes such that the accurate positioning for the image frame is not made. Therefore, if an alarm is raised and the process is interrupted in response to every abnormality, operation efficiency will be deteriorated rather than improved. Namely, since the operator monitors the photoprinter in the vicinity thereof, for example, in case of operating in a manual mode, the abnormality can be eliminated without interruption of process in some cases. However, if the processing is interrupted for each detected abnormality, the subsequent action for eliminating the abnormality results in the reduced operation efficiency. On the other hand, in case of a fully automatic mode, it is possible to continue the process apart from the finished conditions of the respective prints except for such a case that the stop reference of the image frame can not be analogized. Further, it is a principal object of the operation in the fully automatic mode to process consecutively on condition that reprint process can be performed later. Accordingly, it is undesirable to interrupt the process to give the alarm in response to each abnormality except that the stop reference of the image frame can not be analogized.